An input-output circuit capable of eliminating ringing by cooperation of an input circuit and an acceleration circuit has been known (see Patent Literature 1). Data lines outside a chip connected to an I/O terminal are doubly driven by two transistors, facilitating potential drop of a node. After a predetermined time passes, when level of the node is determined to be L logic, H logic is outputted from the input circuit, and thereby transistors of the acceleration circuit turn off. Data lines outside the chip connected to the I/O terminal are singly driven by one output transistor, and thus potential variations of the node become gradual, avoiding waveform distortion such as ringing.
There has been known a data output circuit having a transmission line driving unit which drives a transmission line according to input data, and a data transition detection unit which detects a transition of input data or a transition of output data of the transmission line driving unit (see Patent Literature 2). For a predetermined period since the data transition detection unit detected a transition of data, driving capability of the transmission line driving unit is enhanced.
Patent Literature 1: Japanese Laid-open Patent Publication No. 6-104725 Patent Literature 2: Japanese Laid-open Patent Publication No. 11-239049
Double driving by two transistors enables fast driving. However, when driving capability is enhanced, an impedance mismatch occurs, and an overshoot or an undershoot of output voltage occurs, making it not possible to transmit a desired signal.